Conventional lawn mowers designed to cut a relatively wide swath across grass have existed for a considerable length of time. Likewise, devices specifically designed to clean up rough edges left by a conventional mower, or not readily accessible by a conventional mower, have existed for a significant period of time. Devices of the latter kind are commonly referred to as lawn trimmers or lawn edgers.
The fact has been recognized that advantages may flow from combining features of a lawn trimmer with a lawn mower. For example, U.S. Pat. No. 4,653,254 granted to Qualls on March 31, 1987, discloses a lawn trimmer apparatus and mower combination in which the trimmer apparatus derives operating power from the lawn mower engine. However, the essential feature of the Qualls design appears to be the power take-off mechanism. The trimmer apparatus per se is otherwise designed to be hand held and controlled much like a conventional stand-alone lawn trimmer. The lawn mower does not assist positioning and control of the trimmer.
An example where a lawn mower is used to assist the positioning and control of a lawn trimmer is disclosed in U.S. Pat. No. 4,453,372 granted to Remer on June 12, 1984. Remer discloses a trimmer assembly which is mounted to one side of a lawn mower body by means of a universal or ball joint, and in which a trimmer head is mounted at the end of a telescoping arm from the ball joint, and the head may be rotated to cut in a horizontal or vertical plane (or in between) at that end. However, although the Remer design permits positioning of the trimmer head either by moving the lawn mower or by rotating or extending the telescoping arm, the extent of manipulative control is limited. The control is primarily rotational and radial relative to a fixed point on the lawn mower body and, as noted above, it is oriented to one side of that body. In the result, a substantial amount of "jockeying" of the lawn mower will be required to achieve some cutting operations. The severity of this disadvantage is more limited with a relatively small push-type power mower as is shown in the patent to Remer. In most cases, the user can quickly move the entire mower back and forth and he can quickly turn the entire mower from one direction to another. However, these kinds of movements become more difficult with larger machines such as riding mowers and the requirement for an undue amount of "jockeying" becomes an aggravated disadvantage.
A riding mower which also includes a lawn trimmer apparatus is disclosed in U.S. Pat. Nos. 4,546,601 and 4,663,920 granted to Skovhoj on Oct. 15, 1985, and May 12, 1987, respectively. As in the case of Remer, the movement of the trimmer assembly is rotational relative to a fixed point on one side of the mower body. However, instead of controlling the reach of the trimmer assembly with a telescoping arm, Skovhoj uses an articulated boom mechanism which appears sized to extend on either side and in front of the mower. The boom mechanism is undoubtedly workable. However it would be mechanically cumbersome and appears difficult to manipulate and position with a high degree of precision. In order to reach from one side of the lawn mower body to the other, the boom is lengthy and the trimmer head will be susceptible to a significant degree of bounce at the end of the boom. Further, to trim along a straight line in advance of the mower would require the operator to extend or retract the boom while simultaneously rotating the boom (the same would be true in the case of Remer).
It is an object of the present invention to provide a new and improved lawn trimmer apparatus to be carried by a lawn mower.
A more specific object of the present invention is to provide a lawn trimmer apparatus which, when carried by a lawn mower, enables the user to perform trimming operations over a broad sweep with improved means for positioning a trimmer head in relation to the lawn mower body.
In a broad aspect of the present invention, there is provided a lawn and garden trimmer apparatus comprising a supporting framework and means for mounting the framework to a lawn mower body. A guide rail with a carrier bracket moveably mounted thereon is supported longitudinally between opposed sides of the framework, the carrier bracket serving as a pivotal base connection for a support arm which carries a lawn trimmer assembly at its outer end. The trimmer assembly may thus be positioned not only by rotation of the support arm in relation to the carrier bracket, but also by linear movement of the carrier bracket along the length of the guide rail. The framework and the guide rail advantageously extend across the full front width of the mower permitting trimming operations in advance and on either side of the mower. Although such trimming operations may be generally achieved with a design such as that of Skovhoj, the absence of a fixed position base in the case of the present invention enables the use of a relatively short pivotable support arm (viz. compared to the boom assembly of Skovhoj) while maintaining a substantual area of positioning and cutting sweep for the trimmer assembly.
Further, and as will become more apparent hereinafter, the invention may be implemented with a compact, low profile configuration with the trimmer assembly, including its supporting framework, distanced away from the user without the necessity for a lengthy support arm or boom to achieve the desired reach. In the case of a reel type mower, the supporting framework for the trimmer assembly may be advantageously integrated with framework used to support the reel (or reels).
The present invention is considered to be particularly suitable for use with riding mowers in that it reduces the need to "jockey" the entire mower for some trimming operations. However, it may also be used with push type mowers.
The foregoing and other features and advantages of the invention will now be described with reference to the drawings.